|Beta sitosterol is a phytosterol that have structural similarity to the cholesterol made in our bodies. There are over 40 phytosterols, but beta-sitosterol is the most abundant one, comprising about 50% of dietary phytosterols. Other phytosterols include
campesterol, stigmasterol, brassicasterol, delta-7-stigmasterol and delta-7-avenasterol. Phytosterols are waxy, clear solids soluble in most organic solvents but insoluble in water, and contain one alcohol functional group. Phytosterols are found in most plants and thus in foods such as rice bran, wheat germ, corn oils, soybeans, and peanuts. As one of several phytosterols, beta-sitosterol is commonly found in foods such as wheat germ, soybeans, and corn oil. It is also widely distributed in the plant kingdom and found in such botanicals as Serenoa repens (saw palmetto), Curcurbita pepo (pumpkin seed) and Pygeum africanum. The best way to obtain beta-sitosterol is to eat a diet rich in fruits, vegetables, nuts and seeds.
Beta-sitosterol is used for lowering cholesterol and easing symptoms of benign prostatic hyperplasia (BPH). Phytosterols inhibit the absorption of dietary cholesterol and the reabsorption (via the enterohepatic circulation) of endogenous cholesterol from the gastrointestinal tract. Beta sitosterol inhibits intestinal absorption of cholesterol by competing for the limited space for cholesterol in mixed micelles. Beta-sitosterol normalizes blood sugar and insulin levels in Type II diabetics by stimulating the release of insulin in the presence of non-stimulatory glucose concentrations, and inhibiting glucose-6-phosphatase. Beta-sitosterol seems to reduce the cholesterol level in the prostate. Beta-sitosterol might also work through its anti-inflammatory activity. Beta-sitosterol is found to reduce the growth of human prostate and colon cancer cells. It also acts against lymphocytic leukemia. Beta-sitosterol also appears to modulate immune function, inflammation and pain levels through its effects on controlling the production of inflammatory cytokines.